Not all human societies have had writing and even fewer had it in any significant way. Secondly, oral traditions are not always about entertainment nor are they

Not all human societies have had writing and even fewer had it in any significant way. Secondly, oral traditions are not always about entertainment nor are they only recorded by writing. There's a very common trap when considering the past to look for "logical causation". It's almost always incorrect to do so and leads to this sort of wild speculation.